Introducer Handle Notch Design/Concept

ABSTRACT

An improved splittable medical device introducer designed to introduce a medical device such as a lead or catheter, into a patient&#39;s vasculature without loss of blood or introduction of air is described. The introducer assembly is designed with a notch provided at the proximal end of the introducer housing. The notch, which may comprise a multitude of cross-sectional geometries, is designed to reduce the force required to separate the housing and the introducer sheath, thereby minimizing the possibility of unintentional dislodgement during separation. The notch also increases the repeatability and consistency of the amount of force required to separate the introducer housing and sheath.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application Ser.No. 61/510,510, filed on Jul. 22, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to introducers and introducingassemblies. Specifically, the present invention is directed to asplittable introducer with a notched housing.

2. Prior Art

Introducer devices provide for access to the venous system and areemployed for inserting medical devices such as catheters, guidewires,leads, infusion ports, dialysis ports, dialysis catheters, and others. Atypical procedure for gaining access to the central venous system or thearterial system with an introducer is the Seldinger Introduction Method.The Seldinger Method provides for insertion of a needle into thevasculature of a patient. Once the needle is in the vessel, thephysician aspirates the needle with a syringe to assure that the needleis in the vessel, and to draw out air present in the bore of the needle.The syringe is removed and discarded. A guide wire is inserted throughthe needle, and the needle is removed over the guide wire. Theintroducer, which includes a dilator and a sheath, is placed over theguidewire and inserted into the vessel. With the introducer and wireguide in the vessel, the dilator and wire guide are removed leaving onlythe sheath in the vessel. The desired medical device is implantedthrough the passage of the sheath. The sheath is optionally removed fromthe medical device.

The standard method for accomplishing sheath housing separation is by amechanical breaking or cracking of the sheath housing in two halves.However, there are problems associated with this method.

First, the force required to initiate sheath housing separation forprior art introducers is relatively high. The application of such arequired force may not be possible due to the varying physical strengthsof care providers. Furthermore, exerting such an increased amount offorce on the introducer device may result in the unintentional movementor dislodgement of the device within the vasculature.

Second, the housing of prior art introducers requires a thin wallthickness. This thin wall thickness is necessitated to promote theinitiation and propagation of the crack required to separate thehousing. However, the addition of desirable ergonometric and aestheticfeatures increase the thickness and complexity of the housing, therebyincreasing the difficulty and force needed to separate the housing. Inaddition, such complexities are difficult to manufacture and producesuch that the housing consistently splits apart with the application ofa repeatable and consistent force.

Therefore, what is desired is an introducer device comprising a housingthat separates at a reduced force to initiate subsequent splitting orseparation of the sheath. In addition, an introducer housing thatrepeatably and consistently separates upon the application of aconsistent separation force is desired. Furthermore, an introducerassembly that is able to be manufactured more easily and consistently isdesired.

SUMMARY OF THE INVENTION

An introducer assembly comprising a notched housing is provided herein.The introducer includes a sheath having a sheath proximal end spacedfrom a distal end, and a sheath lumen that extends longitudinallytherethrough. In addition, the introducer assembly of the presentinvention comprises a dilator subassembly. The dilator subassemblycomprises a dilator sheath having a dilator sheath proximal end spacedfrom a dilator sheath distal end. The dilator is designed such that thedilator sheath is inserted through the lumen of the introducer sheath.

The introducer assembly further comprises a housing subassembly that ispositioned over the proximal end of the sheath. The housing subassemblycomprises a housing body having a housing body proximal end spaced froma housing body distal end. A housing through-bore extends longitudinallytherethrough. A score-line residing within a portion of the thickness ofthe exterior surface of the housing extends from the housing bodyproximal end to the housing body distal end.

Positioned at the proximal end of the housing body is a notch thatextends at least part way through the thickness of the sidewall andextends from the proximal end of the housing body. This notch, which cancomprise a multitude of geometric shapes, is design to concentrateapplication of the separation force to a specific area or point thusreducing the force required to initiate and propagate the separationcrack through the sidewall of the housing body for separating thehousing in two.

In addition, a retainer ring may be provided. The retainer ring isdesigned to act as a temporary valve to prevent the flow of fluids, gasand liquid, through the notch of the housing body. The ring ispositioned within or adjacent the throughbore at the proximal end of thehousing body. A tab extending from the perimeter wall of the ring ispositioned within the opening of the notch to thereby prevent potentialfluid flow therethrough.

Advantageously, the introducer assembly described above provides manybenefits. For example, the introducer assembly allows for a removableintroducer assembly to seal against instruments such as leads or otherinstruments and devices. These and other embodiments, aspects,advantages, and features of the present invention will be set forth inpart in the description which follows, and in part will become apparentto those skilled in the art by reference to the following description ofthe invention and referenced drawings. The aspects, advantages, andfeatures of the invention are realized and attained by means of theinstrumentalities, procedures, and combinations particularly pointed outin the appended claims and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an embodiment of an introducerassembly device of the present invention.

FIG. 1A shows a perspective view of the components comprising theintroducer assembly shown in FIG. 1.

FIG. 2 illustrates a perspective view of a prior art introducer housingsubassembly.

FIG. 3 shows a side view of an embodiment of an introducer housingsubassembly comprising a notch stress confining feature of the presentinvention.

FIG. 3A illustrates a magnified view of the embodiment of the notchstress confining feature shown in FIG. 3.

FIG. 4 shows a side view of an introducer housing subassembly comprisingan alternate embodiment of a stress confining feature of the presentinvention.

FIG. 5 shows a side view of an introducer housing subassembly comprisingan alternate embodiment of a stress confining feature of the presentinvention.

FIG. 6 illustrates an embodiment of a retainer ring of the presentinvention.

FIG. 7 illustrates the embodiment of the retainer ring of FIG. 6 beingpositioned within the introducer assembly of the present invention.

FIG. 7A shows a magnified view of the retainer ring, shown in FIG. 6,positioned within the introducer assembly.

FIG. 8 illustrates an embodiment of the housing subassembly comprising abreak-away flap feature.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Now referring to the figures, FIGS. 1 and 1A illustrate an embodiment ofan introducer assembly 10 of the present invention. The introducerassembly 10 comprises an elongated introducer sheath 12 connected to anintroducer housing subassembly 14. The sheath 12 is an elongate memberhaving an introducer sheath sidewall 16 extending along a longitudinalaxis A-A from a sheath proximal portion 18 to a sheath distal end 20.The thickness of the sidewall 16 including the proximal section 18extending to the distal end 20 is from about 0.001 inches to about 0.050inches.

A lumen or passage 22 provides for open communication along the entirelength of the sheath 12 and into the introducer housing subassembly 14.This lumen 22 allows for a medical device, such as a lead or catheter,to be advanced through the assembly 10. The lumen 22 preferably has adiameter from about 0.05 inches to about 0.50 inches.

In addition, as shown in FIGS. 1 and 1A, the introducer assembly 10 ofthe present invention comprises a dilator subassembly 24. As shown, thedilator subassembly 24 comprises an elongated dilator sheath 26connected to a bulbous dilator head 28. The dilator head 28 comprises adilator head through-bore 30 which extends longitudinally through thelength of the dilator head 28. The dilator sheath 26 is an elongatemember having a dilator sheath sidewall 32 extending along alongitudinal axis B-B from a dilator sheath proximal portion 34 to adilator sheath distal end 36. The thickness of the dilator sheathsidewall 32, including the proximal section 34 extending to the distalend 36, is from about 0.001 inches to about 0.050 inches. The diameterof the distal end 36 of the dilator sheath 26 may be narrow than thediameter of the proximal end portion 34 of the dilator sheath 26. Asshown, the distal end 36 of the dilator sheath 26 may comprise a pointedend 38.

The dilator sheath 26 is designed such that it may be inserted withinthe introducer sheath lumen 22 and extends longitudinally along axisA-A. As shown, the dilator head 28 mates with the housing subassembly14. In a preferred embodiment, a proximal portion 40 of the dilator head28 comprises a helical ridge or thread 42 positioned along an exteriorsurface 44 of the dilator head 28. The helical ridge 42 is designed tothreadingly engage within a corresponding groove 46 residing within aninterior surface 48 of the housing subassembly 14. When the dilator 24is positioned within the lumen 22 of the sheath 12, the dilator head 28is rotated to threadingly engage the helical ridge 42 within the groove46 of the housing subassembly 14 forming a secure fit therebetween. Thedilator 24 may be removed from the sheath 12 by reversing the rotationof the dilator head 28 and removing the dilator from the sheath 12 ofthe introducer 10.

The housing subassembly 14 comprises a housing body 50 having a housingbase portion 52 that fluidly extends to an upper housing web portion 54.As shown, a housing through-bore 56, defining a housing sidewall 58,extends longitudinally along axis A-A. A portion of the sheath proximalregion 18 is supported within the through-bore 56 of the housingsubassembly 14. More specifically, the portion of the sheath proximalregion 18 is designed to be positioned within the through-bore opening56 of the housing 50, such that the opening of the lumen 22 and thehousing through-bore 56 are aligned. In a preferred embodiment, the baseportion 52 of the housing body 50 circumferentially extends around anexterior surface 60 of the introducer sheath 12 forming a tightinterference fit therebetween. In a preferred embodiment, the baseportion 52 of the housing body 50 may be molded over the proximal endportion 18 of the sheath 12.

Residing within the upper web portion 54 of the housing body 50 is astress confining feature 62. More specifically, the stress confiningfeature comprises a notch 64 that extends from a proximal end 66 of theupper web portion 54 of the housing body 50 to a stress concentrationarea or point 68 (FIGS. 3 to 5), distal of the proximal end 66. Thenotch 64 preferably extends through at least a portion of the thicknessof the housing body sidewall 58. Alternatively, as shown in theembodiment of FIG. 3, the notch 64 may extend through the entirethickness of the sidewall 58 of the web portion 54 of the housing 50.

A score-line 70 extends distally from the stress concentration area orpoint 68 of the stress concentration notch 64. The score-line 70preferably resides within a portion of an exterior surface 72 of thehousing body 50. In a preferred embodiment, the score-line 70 extendsfrom the stress concentration point 68 of the notch 64 to a distal end74 of the base portion 52 of the housing 50. As will be shown in thefollowing examples and illustrations, the housing subassembly 14 of theintroducer assembly 10 of the present invention may comprise a multitudeof non-limiting notch geometries.

In addition, extending from the housing body 50, are spaced apart wings76 and 78, which give the housing body 50 a butterfly appearance. Morespecifically, the opposing left and right wings 76, 78 fluidly extendfrom an exterior surface 80 of the upper web portion 54 of the housingbody 50. These wings 76, 78 are designed such that when a downward andcounter rotated force is applied to them, a separation force is therebyapplied to the stress concentration feature 62 or notch 64 of thehousing body 50. The notch 64 then focuses the separation force to thestress concentration point 68 were a housing separation crack isinitiated. Upon the application of an additional opposed lateral pullingforce, the initiated crack propagates along the score-line 70 therebyseparating the housing subassembly 14 and introducer sheath 12.

In contrast, an embodiment of a housing subassembly 82 of the prior art,as shown in FIG. 2, does not comprise such a stress confining feature ornotch. As shown, the prior art housing 82 comprises only the score-line70 that extends longitudinally from its proximal portion to the distalportion of the housing 82. The lack of such a stress confining feature62 such as the present notch 64 means that a relatively greater force isrequired to separate the prior art housing 82 to initiate subsequentsplitting separation of the sheath 12.

FIGS. 3, 3A, 4 and 5 illustrate preferred embodiments of introducerhousing subassemblies. Specifically, FIGS. 3, 3A, 4 and 5 show preferredembodiments of various stress confining features 62 of the presentinvention. In particular, FIGS. 3 and 3A illustrate an embodiment of anintroducer housing subassembly 84 comprising a notch 86 having arectangular cross-section. As shown, the notch 86 is formed by removinga portion of the thickness of the sidewall 58 of the upper web portion54 of the housing 84. More specifically, as shown in FIG. 3A, the notch86 comprises a notch width 87, a notch length 89, and a notch depth. Ina preferred embodiment, the notch width 87 may range from about 0.01inches to about 0.25 inches, the notch length 89 may range from about0.01 inches to about 0.25 inches, and the notch depth may also rangefrom about 0.01 inches to about 0.25 inches. In a preferred embodiment,the width of the notch 86 may be greater than the width of the prior artscore-line 70 (FIG. 2). The length of the notch 86 may also range fromabout 5% to about 50% of the length of the upper web portion 54 of thehosing body 50. Furthermore, the depth of the notch 86 may be aboutequal to the thickness of the sidewall 58 of the housing 50,particularly the sidewall thickness of the upper web portion 54 of thehousing 50.

FIG. 4 illustrates an alternate embodiment of an introducer housingsubassembly 88 comprising a notch 90 having a “V” or wedge-likecross-section. As shown this notch 90 comprises a first notch sidewall92 and a second notch sidewall 94 that converge at the stressconcentration point 68. In a preferred embodiment, each of the first andsecond sidewalls 92, 94 has a notch angle 96 that ranges from about 5°to about 90°. The notch angle 96 is defined as the angle betweenlongitudinal axis A-A and a surface 98 of the notch sidewall 92, 94. Thefirst or second notch sidewalls 92, 94 may have a similar or differentnotch angle 96. The notch also comprises a notch depth that approximatesthe thickness of the sidewall 58 of the web portion 54 of the housingbody 50.

FIG. 5 illustrates yet another alternate embodiment of an introducerhousing subassembly 100 comprising a notch 102 having a curvedcross-section. As shown, the notch 102 comprises a curved surface 104that resides within a portion of the thickness of the sidewall 58 of thehousing body 50. In a preferred embodiment, the curved surface of thenotch has a notch radius of curvature that ranges from about 0.1 inchesto about 0.25 inches.

The notch 102 comprises a notch depth 106 that penetrates through aportion of the length of the web portion 54 of the housing 50. As shown,the notch depth extends from the proximal housing end 66 of the upperweb portion 54 to a point distal of the proximal end 66. In a preferredembodiment, the notch depth 106 may range from about 0.01 inches toabout 0.25 inches. Alternatively, the notch depth 106 may range fromabout 5 percent to about 25 percent of the length of the web portion 54.The notch also comprises a notch width that may span about the thicknessof the sidewall of the upper web portion 54.

Test Data

A series of mechanical tests were performed comparing the measuredseparation force of the introducer assembly 10 of the present inventionto that of the force required to separate the housing 82 of the priorart (FIG. 2). Specifically, introducer assemblies 10 comprising thecurved notch housing subassembly embodiment 100 (FIG. 5) were testedagainst the housing 82 of the prior art introducer assembly illustratedin FIG. 2.

Table I, shown below, summarizes the mechanical test data of theintroducer assembly of the prior art. As shown, the average measuredforces required to separate the housing 82, of various introducerdiameters, i.e., French sizes, of the prior art design are detailedbelow in Table I. During the test, separation forces were measured andaveraged for a total of 10 introducer samples per French size, sizes 7French to 17 French in total. The French size scale is commonly used inthe medical device arts to denote the diameter of a lead or a catheter.A French size of 1 equates to a diameter of about 0.33 mm.

TABLE I Dia. 7 8 9 10 11 12 13 14 15 16 17 Fr Fr Fr Fr Fr Fr Fr Fr Fr FrFr Avg. 14.8 18.0 17.2 17.5 15.1 14.2 16.2 17.6 17.8 19.0 16.6 Force(lbs-f) Std. 0.5 0.2 0.3 0.4 0.4 0.3 1.5 0.9 0.4 0.9 0.5 Dev. Cpk 3.64.6 2.8 1.9 4.7 5.9 0.8 0.9 1.7 0.4 2.5

Table II, shown below, summarizes the mechanical test data of the forcerequired to separate the housing subassembly 100 of the presentinvention among various French sizes. More specially, separation forceswere measured and averaged on a total of 10 introducer samples perFrench size, sizes 7 French to 17 French in total. The test samplescomprised the curved notch feature embodied in FIG. 5.

TABLE II Dia. 7 8 9 10 11 12 13 14 15 16 17 Fr Fr Fr Fr Fr Fr Fr Fr FrFr Fr Avg. 11.4 13.6 13.6 13.2 10.6 9.8 11.4 13.2 14.0 14.9 12.7 Force(lbs-f) Std. 0.4 0.4 0.3 0.3 0.4 0.2 0.4 0.6 0.8 0.6 0.6 Dev. Cpk 6.65.0 6.2 9.0 7.2 16.4 7.5 4.0 2.4 2.9 4.3

As can be seen from the test data, the overall average force required toseparate the notched housing 100 of the introducer assembly 10 of thepresent invention was less than the average force required to separatethe housing 82 of introducer assembly of the prior art. The test datatherefore, illustrates a direct reduction in the separation force of theintroducer assembly 10 of the present invention comprising the notchedhousing 100.

In addition, the increased process capability index values (Cpk)resulting from the testing of the introducer design of the presentinvention, as shown in Table II, illustrate the increased repeatabilityof the force required to separate the test samples. Process capabilityindex is herein defined as a statistical measure of process control. Thegreater the Cpk value, the greater the repeatability and control theprocess, or in this case, the measured separation force values.

TABLE III Dia. 7 8 9 10 11 12 13 14 15 16 17 Fr Fr Fr Fr Fr Fr Fr Fr FrFr Fr Percent 22.5 24.2 20.6 24.4 29.9 30.8 29.7 25.1 21.1 21.5 23.3Diff.

Table III details the percent difference in the average measured forcesrequired to separate the respective housing subassemblies. As shown, theaverage force required to separate the housing assembly 82 of the priorart design was greater for every diameter size. For example, the forcerequired to separate a 10 French diameter prior art introducer assemblymeasured, on average, about 17.5 lb-force. In comparison, the averageforce required to separate the housing 100 of the introducer assembly 10of the present invention comprising the curved notch 102 measured about13.2 lb-force. This, as shown in Table III, corresponds to a reductionin separation force of about 24.4 percent. Therefore, as can be seenfrom the test data above, the force required to separate the notchedintroducer assembly of the present invention is not only less than theforce required to separate the introducer assembly of the prior art butalso exhibits greater consistency and repeatability.

FIGS. 6, 7 and 7A, illustrate an embodiment of a retainer ring 108. Theretainer ring 108 may be used with the introducer assembly 10 of thepresent invention as a means to prevent the possible flow of fluids suchas a gas or liquid through the opening of the notch 64. The ring 108 isdesigned to be either placed adjacent to or inserted within the proximalend 66 of the housing subassembly 14. As shown, the retainer ring 108comprises an annular retainer body 110 in which a retainer through-bore112 extends. Extending from a perimeter sidewall 114 of the ring 108 isa tab 116 that is designed to be inserted within the notch 64 of thehousing body 50. In a preferred embodiment, at least two opposing tabs116 project from the perimeter sidewall 114 of the retainer ring 108.The tab or tabs 116 are dimensioned to fit within the opening of thenotch 64. In a preferred embodiment, the tab 116 is of a rectangularcross-section however, the tab 116 may comprise a cross-sectionaldimension such that the tab 116 fits within the various embodiments ofthe notches.

As shown in FIG. 7, the retainer ring 108 maybe positioned over orwithin the through-bore opening of the proximal end 66 of the housingsubassembly 14. A clip 118 portion of the housing body 50, as shown inFIG. 7A, may be used to hold the retainer ring 108 in place within orover the through-bore 56 of the proximal end 66 of the housingsubassembly 14. The clip 118 is positioned within a recess 119 of theperimeter sidewall 114 of the retainer ring 108 (FIG. 6). The clips 118are diametrically opposite to each other and preferably offset 45° fromthe tabs 116.

FIG. 8 illustrates yet another alternate embodiment of a housingsubassembly 120 of the present invention. Similar to the previousembodiments of the housing subassemblies, this embodiment comprises ahousing body 122 having opposing left and right wings 76, 78 that extendfrom the exterior surface 72 of the body 122. Similar to the previoushousing subassemblies of the present invention, the score-line 70resides within a portion of the thickness of the exterior surface 72extending from the upper web portion 54 to the distal base portion 52 ofthe housing 120. The central throughbore 56 extends therethrough.

However, unlike the previous embodiments of the housing subassemblies,this embodiment 120 comprises a flap 124 that is designed to break awaywhen a force is applied to the left and right wings 76, 78. Furthermore,the housing subassembly 120 comprises a series of raised ridges 126residing within the left and right wings 76, 78. These ridges 126 aredesigned to add strength and rigidity to the wings 76, 78.

In an embodiment, the flap 124 is connected between the opposing leftand right wings 76, 78 of the housing subassembly 120, such as bymolding. More specifically, as shown in FIG. 8, the flap 124 ispositioned and connected between respective left and right sides 122A,122B of the upper housing portion 54. Each flap 124 resides within acorresponding notch 128 within the sidewall 58 of the housing upperportion 54 of the housing subassembly 120. In an embodiment, each flap124 may be composed of a rigid polymeric material that easily breaksunder a mechanical stress. In addition, the flap 124 may be composed ofsantoprene, silicone, polyether block amides and the like.

When a force is applied to the opposing left and right wings 76, 78 theflap 124 breaks off, of the left and right side 122A, 122B of the upperhousing portion 54, thereby exposing the notch 64 positioned within thesidewall 58 of the housing body 122. Thus, when the flap 124 breaks off,the notch 128 concentrates application of the separation force to thescore-line 70, thereby initiating a separation crack therebetween.

In operation, the dilator 24 is received inside the lumen 22 of theintroducer sheath 12. This allows for the introducer assembly to beintroduced into the vasculature of a patient, for instance, over a guidewire (not shown). This positions the distal end 20 of the sheath 12inside the vasculature while the proximal section 18 and the housingsubassembly 14 remain outside the patient. After the introducer assembly10 is inserted into a patient and the dilator has been removed from thesheath 12, other medical instruments can be easily inserted into andthrough the sheath 12 and introduced into the patient. The retainer ring108 may be positioned within the through-bore 56 of the housingsubassembly 14 at its proximal end 66 to prevent blood and other bodyfluids from leaking out of the vasculature and outside air from gettingin.

Then, once the lead or catheter is properly positioned in thevasculature, the introducer assembly 10 of the present invention issplit apart for removal from the vasculature. This is done by holdingthe wings 76, 78 between the thumb and fore finger and counter rotatingthem with respect to each other while slowly moving the wings furtherapart. The housing body 50 is readily separated. This occurs at thescore-line 70 that runs along the base portion 52 of the housing body50.

As the wings 76, 78 of the housing 50 are moved apart, the resultinghalves of the housing begin to exert a force on the proximal end 18 ofthe sheath 12. These forces are concentrated at the notch 64,particularly at the stress concentration point 68 to initiate a tear atthe proximal end of the score-line 70. The force generated by furthermanipulation of the wings 76, 78 is concentrated at the lower extent ordistal stress point/area 68 of each notch feature 64. This concentratedforce is sufficient to cause the material of the housing subassembly 14to sever or tear apart from the sheath 12.

The housing subassembly 14 of the present invention is preferablycomposed of an acrylic based poly maretial, such as polymethylmethacrylate. In addition, the housing subassembly 14 may also becomposed of ethyl acrylate, 2-chloroethyl vinyl ether, 2-ethylhexylacrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylateand the like.

The sheath 12 of the present invention preferably comprisespolytetrafluoroethylene (PTFE). While PTFE is the most preferredmaterial for the housing 14, other fluoropolymeric materials may also beused. These include polyhexafluoropropylene,tetrafluoroethylene-hexafluoropropylene copolymers,tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers,polytrifluoroethylene, ethylene-tetrafluoroethylene copolymers,fluoroethylene-hydrocarbon vinyl ether copolymers,polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylenecopolymers, polyvinyl fluoride, polyvinylidene fluoride, vinylidenefluoride-hexafluoropropylene copolymers, fluorinated (meth)acrylateresins, 2-fluoroacrylate resins, fluorinated epoxy resins, fluorinatedepoxy (meth)acrylate resins, fluorinated polyether resins, fluorinatedpolyimide resins, fluorinated polyester resins, fluorinated polyamideresins, fluorinated polycarbonate resins, fluorinated polyformal resins,fluorinated polyketone resins, fluorinated polyazomethine resins,fluorinated polyazole resins, and fluorinated polyallyloxysilane resins,vinylidene fluoride-hexafluoropropylene fluoroelastomer, vinylidenefluoride-tetrafluoroethylene fluoroelastomer,tetrafluoroethylene-perfluoroalkyl vinyl ether fluoroelastomer,vinylidene fluoride-tetrafluoroethylene-hexafluoropropylenefluoroelastomer, vinylidene fluoride-tetrafluoroethylene-perfluoroalkylvinyl ether fluoroelastomer, tetrafluoroethylene-perfluoroalkyl vinylether fluoroelastomer, propylene-tetrafluoroethylene fluoroelastomer,fluorosilicone rubber, fluorinated phosphazene rubber, fluorinatedthermoplastic rubbers, and flexible fluorocarbon resins.

The present invention thus provides the upper web portion 54 of theintroducer 10 with structures that concentrate the tearing forcescreated by moving the wings 76, 78 apart to stress confining features 62located diametrically opposite each other in the housing sidewall 58.However, the present invention is not meant to be limited to the notchembodiments discussed and illustrated. Any structure located at theupper web portion 54 of the housing body 50 that serves to concentratethe tearing forces to a confined area is contemplated by the scope ofthe present invention.

Thus, the present invention has described several structures suitable asstress confining structures for concentrating the separating forcesexerted at the upper web portion 54 of the housing body 50 by a pullingmanipulation of the wings 76, 78. In each structure, the total forcesimparted to the wings 76, 78 are concentrated at either diametricallyopposed surfaces along the proximal end 66 of the upper web portion 54.Together with the unique molecular properties afforded by PTFE as thepreferred material for the sheath 12, once a tear begins it propagatesthe entire length of the sheath, no matter how long, in an extremelysmooth manner that provides the physician with a very desirable tactilefeel.

It is, therefore, apparent that there has been provided, in accordancewith the present invention, an introducer assembly comprising a housingsupported on the proximal end of a sheath having a novel structure forremoval from the venous system of a patient. While this invention hasbeen described in conjunction with preferred embodiments thereof, it isevident that many alternatives, modifications, and variations will beapparent to those skilled in the art. Accordingly, it is intended toembrace all such alternatives, modifications and variations that fallwithin the broad scope of the appended claims.

1. An introducer, comprising: a) a sheath comprising a sheath sidewalldefining a sheath lumen, the sheath comprising a length extending from aproximal sheath portion having a proximal sheath end to a sheath distalend; b) a housing body comprising a housing sidewall extending along ahousing length from a proximal housing end to a distal housing portionhaving a distal housing end, the housing sidewall defining a housingthrough-bore extending along a longitudinal axis, wherein the housingsidewall has a thickness spaced from the longitudinal axis, and whereinwith the distal housing portion secured to the proximal portion of thesheath, the housing through-bore provides for passage of a medicaldevice through the housing body and into the sheath lumen; c) at leastone stress confining notch extending through the thickness of thehousing sidewall from the proximal housing end partway along the housinglength to a stress concentration point spaced from the distal housingend; and d) wherein the housing is manipulatable to cause a separationforce to be applied to the stress concentration point to therebyseparate the housing body and the sheath into two generally equal halvedalong a first plane aligned with the longitudinal axis.
 2. (canceled) 3.The introducer of claim 1 wherein the notch comprises a curved crosssection that extends from the proximal housing end to the stressconcentration point spaced from the distal housing end.
 4. Theintroducer of claim 1 wherein the notch comprises a rectangular crosssection having a notch length extending distally from the proximalhousing end, a notch width and a notch depth that approximate thehousing sidewall thickness.
 5. The introducer of claim 1 wherein thenotch comprises a “v” or wedge-like cross-section comprising a firstnotch sidewall and a second notch sidewall that converge at the stressconcentration point.
 6. The introducer of claim 5 wherein the first andsecond notch sidewalls are angled from about 5° to about 90° at a notchangle measured from the longitudinal axis to a surface of the first orsecond sidewall. 7.-8. (canceled)
 9. The introducer of claim 1 whereinthe housing body has at least two opposing wings which facilitatemanipulation to initiate a tear along the length of the housing bodybeginning at the stress concentration point.
 10. (canceled)
 11. Theintroducer of claim 1 wherein the housing body is of a material selectedfrom the group consisting of an acrylic polymer, an ethyl acrylate, a2-chloroethyl vinyl ether, a 2-ethylhexyl acrylate, a hydroxyethylmethacrylate, a butyl acrylate, a butyl methacrylate, and combinationsthereof.
 12. The introducer of claim 1 wherein the sheath is composed ofa fluoropolymeric material selected from the group consisting of PTFE,polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylenecopolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers,polytrifluoroethylene, ethylene-tetrafluoroethylene copolymers,fluoroethylene-hydrocarbon vinyl ether copolymers,polychlorotrifluoroethylene, ethylene-chlorotrifluoroethylenecopolymers, polyvinyl fluoride, polyvinylidene fluoride, vinylidenefluoride-hexafluoropropylene copolymers, fluorinated (meth)acrylateresins, 2-fluoroacrylate resins, fluorinated epoxy resins, fluorinatedepoxy (meth)acrylate resins, fluorinated polyether resins, fluorinatedpolyimide resins, fluorinated polyester resins, fluorinated polyamideresins, fluorinated polycarbonate resins, fluorinated polyformal resins,fluorinated polyketone resins, fluorinated polyazomethine resins,fluorinated polyazole resins, and fluorinated polyallyloxysilane resins,vinylidene fluoride-hexafluoropropylene fluoroelastomer, vinylidenefluoride-tetrafluoroethylene fluoroelastomer,tetrafluoroethylene-perfluoroalkyl vinyl ether fluoroelastomer,vinylidene fluoride-tetrafluoroethylene-hexafluoropropylenefluoroelastomer, vinylidene fluoride-tetrafluoroethylene-perfluoroalkylvinyl ether fluoroelastomer, tetrafluoroethylene-perfluoroalkyl vinylether fluoroelastomer, propylene-tetrafluoroethylene fluoroelastomer,fluorosilicone rubber, fluorinated phosphazene rubber, fluorinatedthermoplastic rubbers, flexible fluorocarbon resins, and combinationsthereof.
 13. (canceled)
 14. (canceled)
 15. The introducer of claim 1wherein the introducer assembly comprises a dilator subassembly, thedilator subassembly comprising an elongated dilator sheath connected toa bulbous dilator head.
 16. An introducer, comprising: a) a sheathcomprising a sheath sidewall defining a sheath lumen, the sheathcomprising a length extending from a proximal sheath portion having aproximal sheath end to a sheath distal end; b) an introducer housingsubassembly comprising: i) a housing body comprising a housing sidewallextending along a housing length from a proximal housing end to a distalhousing portion having a distal housing end, the housing sidewalldefining a housing body through-bore extending along a longitudinalaxis, wherein the housing sidewall has a thickness and wherein with thedistal housing portion secured to the proximal portion of the sheath,the housing through-bore provides for passage of a medical devicethrough the housing body and into the sheath lumen; ii) opposing leftand right wings extending from an exterior surface of the housing body;and iii) at least one stress confining notch extending through thethickness of the housing sidewall from the proximal housing end partwayalong the housing length to a stress concentration point spaced from thedistal housing end; and wherein the housing is manipulatable to cause aseparation force to be applied to the stress concentration point tothereby separate the housing body and the sheath into two generallyequal halved along a first plane aligned with the longitudinal axis. 17.The introducer of claim 16 wherein a score-line extends distally fromthe notch stress confining point to the distal housing end.
 18. Theintroducer of claim 16 wherein the notch comprises a curved crosssection that extends from the proximal housing end to the stressconcentration point spaced from the distal housing end.
 19. Theintroducer of claim 16 wherein the notch comprises a rectangular crosssection having a notch length extending distally from the proximalhousing end, a notch width and a notch depth that approximate thehousing sidewall thickness.
 20. The introducer of claim 16 wherein thenotch comprises a “v” or wedge-like cross-section comprising a firstnotch sidewall and a second notch sidewall that converge at the stressconcentration point.
 21. The introducer of claim 20 wherein the firstand second notch sidewalls are angled from about 5° to about 90° at anotch angle measured from the longitudinal axis to a surface of thefirst or second sidewall. 22.-30. (canceled)
 31. The introducer of claim1 wherein a separation crack is propagatable along a score-line thatextends distally from the stress concentration point to the distalhousing end.
 32. The introducer of claim 1 wherein the housing body hasat least two opposing wings which facilitate manipulation to initiate atear along the length of the housing body beginning at the stressconcentration point.
 33. The introducer of claim 9 wherein an upper wingsurface of each of the two opposing wings meet a proximal housing endsurface at respective obtuse angles.
 34. The introducer of claim 33wherein the stress concentration point resides along a second planealigned normal to the longitudinal axis and wherein the second plane isat a distal location with respect to where the upper wing surfaces meetthe proximal housing end surface at the respective obtuse angles. 35.The introducer of claim 15 wherein a helical thread resides along adilator head exterior surface threadingly engagable within acorresponding groove residing within an interior surface of a proximalhousing portion.
 36. The introducer of claim 16 wherein the introducercomprises a dilator subassembly, the dilator subassembly comprising anelongated dilator sheath connected to a bulbous dilator head.
 37. Theintroducer of claim 36 wherein a helical thread resides along a dilatorhead exterior surface threadingly engagable within a correspondinggroove residing within an interior surface of a proximal housingportion.
 38. The introducer of claim 16 wherein an upper wing surface ofeach of the two opposing wings meet a proximal housing end surface atrespective obtuse angles.
 39. The introducer of claim 38 wherein thestress concentration point resides along a second plane aligned normalto the longitudinal axis and wherein the second plane is at a distallocation with respect to where the upper wing surfaces meet the proximalhousing end surface at the respective obtuse angles.
 40. An introducer,comprising: a) a sheath comprising a sheath sidewall defining a sheathlumen, the sheath comprising a length extending from a proximal sheathportion having a proximal sheath end to a sheath distal end; b) ahousing body comprising a housing sidewall extending along a housinglength from a proximal housing end to a distal housing portion having adistal housing end, the housing sidewall defining a housing through-boreextending along a longitudinal axis, wherein the housing sidewall has athickness spaced from the longitudinal axis, and wherein with the distalhousing portion secured to the proximal portion of the sheath, thehousing through-bore provides for passage of a medical device throughthe housing body and into the sheath lumen; c) at least one stressconfining notch extending through the thickness of the housing sidewallfrom the proximal housing end partway along the housing length to astress concentration point spaced from the distal housing end; and d)wherein the housing is manipulatable to cause a separation force to beapplied to the stress concentration point to thereby cause a separationcrack to propagatable along a score-line extending distally from thestress concentration point and residing within a portion of the exteriorsurface of the housing body.
 41. The introducer assembly of claim 40wherein the introducer assembly comprises a dilator subassembly, thedilator subassembly comprising an elongated dilator sheath connected toa bulbous dilator head.
 42. The introducer assembly of claim 40 whereina helical thread resides along a dilator head exterior surfacethreadingly engagable within a corresponding groove residing within aninterior surface of a proximal housing portion.
 43. The introducer ofclaim 40 wherein the housing body has at least two opposing wings whichfacilitate manipulation to initiate a tear along the length of thehousing body beginning at the stress concentration point.
 44. Theintroducer of claim 43 wherein an upper wing surface of each of the twoopposing wings meet a proximal housing end surface at respective obtuseangles.
 45. The introducer of claim 44 wherein the stress concentrationpoint resides along a second plane aligned normal to the longitudinalaxis and wherein the second plane is at a distal location with respectto where the upper wing surfaces meet the proximal housing end surfaceat the respective obtuse angles.